Liu Wen-qing

Study on Influence of Tetragonal ZrO2 in Oxide Film on Corrosion Resistance of Zr-Sn-Nb Alloy

Abstract Zr-Sn-Nb alloy specimens treated in different ways were exposed to 0.01 mol/L LiOH aqueous solution at 350 °C, 16.8 MPa in autoclave. Spectroscopy Ellipsometry (S-E) was applied to investigate the effect of tetragonal ZrO2 (t-ZrO2) in oxide film on corrosion resistance of Zr-Sn-Nb alloy. It was found that the 580 °C/C. R/500 °C specimen corroded for 42 d and 190 d have more t-ZrO2 than other two specimens. But it is converse to the corrosion rate. It is suggested that the small amount of t-ZrO2 is a main factor to affect the corrosion resistance ability and the corrosion resistance is improved by the formation of t-ZrO2.

Effect of Nb Addition on the Microstructure and Magnetic Properties of Nd 2 Fe 14 B/α-Fe Nanocomposite Magnets

A three dimensional atom probe (3DAP) is used to investigate the effect of Nb addition on the microstructure and magnetic properties of a nanocomposite permanent magnet, Nb₂Fe₁₄B/α-Fe. A Nb-enriched phase has been found to exist in the nanocomposite melt spun ribbons.

The cracking induced by oxidation-hydriding in welding joints of zircaloy-4 plates

The welding joints of Zircaloy-4 plates obtained by diffusion welding at 800X under pressure in vacuum were cracked during autoclave tests at 400X superheated steam after exposure longer than 150 days. The section of specimens was examined by optical microscopy and the composition at the tips of cracking was analyzed by electron microprobe. The result shows that the combination of oxidation and hydriding induced cracking is responsible for this failure of the welding joints.